Acetaldehyde, iron complex

Acetaldehyde, iron complex, 26 23S Acetic acid, chromium, molybdenum, and tungsten complexes, 27 297 palladium complex, 26 208 rhodium complex, 27 292 tungsten complex, 26 224... 

Cyclopentadiene itself has been used as a feedstock for carbon fiber manufacture (76). Cyclopentadiene is also a component of supported metallocene—alumoxane polymerization catalysts in the preparation of syndiotactic polyolefins (77), as a nickel or iron complex in the production of methanol and ethanol from synthesis gas (78), and as Group VIII metal complexes for the production of acetaldehyde from methanol and synthesis gas (79). 

We have delineated viable coordinated ligand reactions and their attendant intermediates for the stoichiometric conversion of CO ligands selectively to the C2 organics ethane, ethylene, methyl (or ethyl) acetate, and acetaldehyde. We now outline results from three lines of research (1) T -Alkoxymethyl iron complexes CpFe(C0)2CH20R (2) are available by reducing coordinated CO on CpFe(C0)3+ (1) [Cp = r -CsHs]. Compounds 2 then form t -alkoxyacetyl complexes via migratory-insertion (i,e. CO... 

Another illustration is given by -complexes of vinyl alcohol that cannot be prepared directly because this ligand cannot exist in the free state it is rapidly converted into its more stable tautomer, acetaldehyde. Iron (158) and platinum (70, 157) complexes of vinyl alcohol have been... 

Aerobic oxidation of alkanes.1 Various metal complexes arc known to catalyze air oxidation of unactivatcd C-—H bonds. Murahashi et al. have found that both ruthenium and iron complexes arc useful catalysts for aerobic oxidation in combination with an aldehyde and an acid. Iron powder is the most effective catalyst, but FeCl3 6H2(), RuCI3 H20, and RuCI2[P(C6H5)3]3 can be used. Useful aldehydes arc hcptanal, 2-mcthylpropanal, and even acetaldehyde. A weak acid is suitable thus acetic acid is preferred to chloroacetic acid. By using the most satisfactory conditions, cyclohexane... 

We believe that catalysis occurs by formation of a complex between acetaldehyde, peracetic acid, and the metal ion in the 3+ oxidation state. The metal ion could be acting as a superacid as for peracetic acid decomposition, although oxidation-reduction reactions within the complex cannot be ruled out. Here again, we have found a disturbing lack of catalytic activity of other trivalent metals (aluminum, iron, and chromium). Simple acid catalysis is not as effective as proved when using p-toluenesulfonic acid and acetyl borate. This indicates that at least more than one coordination position is needed to obtain a complex of the proper configuration. 

The cr-dimethylacetal complex (40) is then hydrolyzed on passage through an alumina column, producing the cr-acetaldehyde complex (38) which is converted to the 7r-vinyl alcohol complex (39) by protonation. Wakatsuki, Nojakura, and Murahashi reported the synthesis of l,3-bis(7r-ethenol)2,4-dichloro- i-dichloroplatinum(II) (41) (42), however, Thyret, who recently reported the NMR evidence for the formation of tetracarbonyl(7r-ethenol)iron (42) at low temperature, could not reproduce the synthesis of (41) (43). 

The structurally-related complex [EtzN] (FeCo3(CO)i2] has also been shown to be an effective catalyst for methanol humoli ation if promoted by methyl iodide and, depending on the reaction temperature, acetaldehyde or ethanol was the major product. The role of iron could not be elucidated. The ammonium ion has been proposed to stabilize by ion pairing anionic complexes wiiich are important in the catalytic cycle [46]. 

Copper chloride complexes can be used as catalysts in a number of organic reactions. Examples include the Wacker process, which is the oxidization of ethylene to acetaldehyde by oxygen and aqueous Cu and Pd precatalysts (or, alternatively using iron catalysts) plus the synthesis of acrylonitrile from acetylene and hydrogen cyanide using CuCl. Cuprous chloride has also been used as a desulfiuizmg and... 

The nse of polysnlfide complexes in catalysis has been discnssed. Two major classes of reactions are apparent (1) hydrogen activation and (2) electron transfers. For example, [CpMo(S)(SH)]2 catalyzes the conversion of nitrobenzene to aniline at room temperature, while (CpMo(S))2S2CH2 catalyzes a number of reactions snch as the conversion of bromoethylbenzene to ethylbenzene and the rednction of acetyl chloride, as well as the rednction of alkynes to the corresponding cw-alkenes. Electron transfer reactions see Electron Transfer in Coordination Compounds) have been studied because of their relevance to biological processes (in, for example, ferrodoxins), and these cluster compounds are dealt with in Iron-Sulfur Proteins. Other studies include the use of metal polysulfide complexes as catalysts for the photolytic reduction of water by THF and copper compounds for the hydration of acetylene to acetaldehyde. ... 

Methyl ethyl ketone, for example is oxidized under mild conditions in the presence of a number of metal complexes in aqueous solution [271-274]. The products of reaction are acetaldehyde and acetic acid. Komissarov and Denisov [272-274] have shown that an iron(III)-o-phenanthroUne complex [272] and a copper(II) pyridine complex [274] catalyze this reaction. In the proposed reaction mechanisms [272, 274] it is suggested that the enolate ion from the ketone is incorporated into the coordination sphere of the metal complex where electron transfer occurs to yield a radical which is attacked by dioxygen, equation (188). In the absence of molecular oxygen, aqueous iron(III) is capable of further oxidizing the radical to form butane 23-dione, equation (189) [271]. 

A Ru(TPFPP)(CO) (4) complex has been prepared, and it was found that 4 is an efficient catalyst for the aerobic oxidation of alkanes using acetaldehyde [140]. Thus, the 4-catalyzed oxidation of cyclohexane with molecular oxygen in the presence of acetaldehyde gave cyclohexanone and cydohexanol in 62% yields based on acetaldehyde with high turnover numbers of 14 100 (Eq. (7.86)). It is worth to note that iron [139] and copper [141] catalysts are also efficient for the oxidation of non-activated hydrocarbons at room temperature under 1 atm of molecular oxygen. 

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